Eucalyptus Versions: 3.3.0 and Greater
Changing Storage Controller Backend Managers
When cloud administrators initially set up Eucalyptus clouds for a small number of users, they will start out with using the Overlay backend  for the Storage Controller. However, over time, as more users begin using the cloud, and begin to use EBS volumes in various ways (i.e. EBS-backed images, multiple EBS volumes attached to an instance, etc.), cloud administrators would like to migrate to a SAN backend for the Storage Controller. This migration can be done in Eucalyptus, however there are a few caveats.
- The caveats with regards to migrating Storage Controller backends are the following:
- Any volumes that want to be migrated need to be backed up before migration to the new backend.
- Data associated with the previous Storage Controller backend will be lost
- Volumes must be detached from instances
Steps to Migrate Storage Controller Backends
Below is an example of changing Storage Controller backends. The example shows the steps to move from the Overlay backend to the Dell Equallogic backend. The steps are as follows:
- Detach volumes from any running instance
- Back up volumes under /var/lib/eucalyptus/volumes directory on Storage Controller (SC)
- Deregister the Storage Controller (SC) - for example:
[root@odc-f-13 ~]# euca_conf --deregister-sc --partition acme --host 10.104.1.194 --component 194-storage-controller
service eucalyptus-cloud restart
[root@odc-f-13 ~]# euca_conf --register-sc --partition acme --host 10.104.1.194 --component 194-storage-controller-equallogic
SERVICE storage acme 194-storage-controller-equallogic LOADED 79 http://10.104.1.194:8773/services/Storage arn:euca:eucalyptus:acme:storage:194-storage-controller-equallogic/
Registered the first storage controller in partition 'acme'. You must choose a storage back end with ``euca-modify-property -p acme.storage.blockstoragemanager=$BACKEND''
[root@odc-f-13 ~]# euca-modify-property -p acme.storage.blockstoragemanager=equallogic
PROPERTY acme.storage.blockstoragemanager equallogic was <unset>
[root@odc-f-13 ~]# euca-modify-property -p acme.storage.sanhost=10.105.2.105
PROPERTY acme.storage.sanhost 10.105.2.105 was <unset>
[root@odc-f-13 ~]# euca-modify-property -p acme.storage.sanuser=grpadmin
PROPERTY acme.storage.sanuser grpadmin was <unset>
[root@odc-f-13 ~]# euca-modify-property -p acme.storage.sanpassword=pwd*4grpadmin
PROPERTY acme.storage.sanpassword pwd*4grpadmin was ********
From there, the EC2 API service provided by Eucalyptus is ready for any EBS related requests.